Method and arrangement for effecting transmission power control and/or handover of a mobile station assigned two or more time slots per frame in a TDMA telecommunications system

ABSTRACT

A method and an arrangement for controlling transmitting power of a mobile station and carrying out a handover in a mobile telecommunications system in which data is transmitted over the radio path between a mobile station and a base station as bursts in time slots of successive frames. A mobile station can be allocated at least two time slots in each frame for high-speed data transmission. The mobile station is arranged to measure the characteristics of the received signal, such as the signal level and/or quality, in each time slot allocated to the mobile station, and the fixed radio network is arranged to control the transmitting power of the mobile station and/or make the decision on a handover on the basis of a combination of measurement results of two or more time slots, or on the basis of the measurement result of the poorest time slot.

FIELD OF THE INVENTION

The present invention relates to methods and an arrangement for powercontrol of a mobile station, and performing a handover in a mobiletelecommunications system in which data is transmitted over the radiopath between a mobile station and a base station of a fixed radionetwork as bursts in time slots of successive frames.

BACKGROUND OF THE INVENTION

In mobile telecommunications systems of the time division multipleaccess (TDMA) type, time division communication in the radio path takesplace in successive TDMA frames each of which consists of several timeslots. In each time slot, a short information packet is sent as a radiofrequency burst of a finite duration, which burst consists of a numberof modulated bits. For the most part, time slots are used for thetransmission of control channels and traffic channels. On the trafficchannels, speech and data are transmitted. On the control channels,signalling between a base station and mobile subscriber stations iscarried out. The Pan-European mobile system GSM (Global System forMobile Communications) is an example of a TDMA radio system.

For communication in conventional TDMA systems, each mobile station isassigned one time slot of traffic channel for data or speechtransmission. Thus, a GSM system, for example, can have as many as eightsimultaneous connections to different mobile stations on a same carrierfrequency. The maximum data transfer rate on a traffic channel isrestricted to a relatively low level according to the bandwidth in useas well as channel coding and error correction, for example in a GSMsystem to 9.6 kbit/s or 12 kbit/s. In addition, in a GSM system ahalf-speed traffic channel (max. 4.8 kbit/s) can be chosen for lowspeeds of speech coding. The half-speed traffic channel is establishedwhen a mobile station communicates in a specific time slot only in everysecond frame, in other words, in half-speed. A second mobile stationcommunicates in every second frame in the same time slot. This is howthe capacity of the system can be doubled as far as the number ofsubscribers is concerned, in other words, on the same carrier wave it ispossible for up to 16 mobile stations to communicate simultaneously.

In the last few years, the need for high-speed data services in mobilecommunication networks has remarkably increased. Data transfer rates ofat least 64 kbit/s would be needed to utilize, for example, ISDN(Integrated Services Digital Network) circuit switched digital dataservices. PSTN data services of the public telephone network, such asmodems and telefax terminals of class G3, require faster transfer rates,such as 14.4 kbit/s. One of the growing areas of mobile data transferrequiring higher transfer rates is the mobile video service. As examplesof this kind of services, security control by cameras and videodatabases can be mentioned. The minimum data transfer rate in videotransfer can be, for example, 16 or 32 kbit/s.

The data transfer rates of the present mobile communication networks arenot, however, sufficient to satisfy this kind of new needs.

SUMMARY OF THE INVENTION

It is an object of the present invention to enable higher data transferrates in mobile communication networks.

Another object of the invention is a handover and power control of amobile station in connection with high-speed data transmission.

This object is achieved by a method for power control of a mobilestation in a mobile telecommunications system which method comprisestransmitting data over the radio path between a mobile station and abase station of a fixed radio network as bursts in time slots ofsuccessive frames, and allocating the mobile station at least two timeslots in each frame for high-speed data transmission, which methodcomprises

measuring the characteristics of the received signal, such as signallevel and/or quality, at the mobile station in each time slot allocatedto the mobile station,

controlling the transmitting power of a mobile station on the basis of acombination of measurement results of two or more time slots, or on thebasis of a measurement result of the poorest time slot.

The invention also relates to a handover method in a mobiletelecommunications system which method comprises transmitting data overthe radio path between a mobile station and a base station of a fixedradio network as bursts in time slots of successive frames, andallocating the mobile station at least two time slots in each frame forhigh-speed data transmission, which method comprises

measuring the characteristics of the received signal, such as signallevel and/or quality, at the mobile station in each time slot allocatedto the mobile station,

making a handover decision on the basis of a combination of measurementresults of two or more time slots, or on the basis of a measurementresult of the poorest time slot.

The invention also relates to a control arrangement of a mobile stationin a mobile telecommunications system in which data is transmitted overthe radio path between a mobile station and a base station of a fixedradio network as bursts in time slots of successive frames, and a mobilestation can be allocated at least two time slots in each frame forhigh-speed data transmission, which arrangement comprises that a mobilestation is arranged to measure the characteristics of the receivedsignal, such as signal level and/or quality, in each time slot allocatedto the mobile station, and that the fixed radio network is arranged tocontrol the transmitting power of a mobile station and/or make ahandover decision on the basis of a combination of measurement resultsof two or more time slots, or on the basis of a measurement result ofthe poorest time slot.

The invention employs a so-called multi-slot technique so that a mobilestation has access to two or more time slots in each frame. Thehigh-speed data signal to be transmitted over the radio path is splitinto a required number of data signals of lower speed, each signal beingtransmitted as bursts in a respective time slot. As soon as the datasignals of lower speed have separately been transmitted over the radiopath, they are again at the receiving end combined into the originalhigh-speed signal. This is how the data transfer rate can be doubled,tripled, etc., depending on whether two, three or more time slots areassigned to be used by a subscriber. In a GSM system, for example, twotime slots will enable a data transfer speed of 2×9.6 kbit/s which isenough for a modem of 14.4 kbit/s, or a telefax terminal, for example.Six time slots will enable a data transfer rate of 64 kbit/s.

The multi-slot technique in accordance with the invention, in which ahigh-speed data signal is transmitted as several bursts in several timeslots within one frame, has many advantages over an alternative approachin which a mobile station is also assigned several time slots in thesame frame for data transmission, but the whole data signal istransmitted as one burst extended for the time of the assigned timeslots. In the present invention, there is no need to change the othersignificant characteristics of the physical transmission path (radiopath, for example, Layer 1 of GSM), such as frequency division, frameformat and time slot configuration, data transfer rate, errorcorrection, modulation, format of a TDMA burst, bit error ratio (BER),etc. In other words, by the present invention it is possible to supportdifferent kind of subscriber data transfer rates in the radio system bya single structure of a physical transmission path. Consequently thereis no need to support several structures of a physical transmission pathby the subscriber terminals, either.

The multi-slot technique of the invention enables that each time slot,i.e. traffic channel, allocated to a mobile station can be handled as anindependent traffic channel with regard to measurements, transmitting ofmeasurement reports, and power control. Each traffic channel is measuredindependently. In the primary embodiment of the invention, it ispossible to carry out the power control and the reporting of measurementresults independently for each time slot by associating an individual,parallel control channel with each traffic channel time slot. This isadvantageous, because the signal quality can vary considerably indifferent time slots due to, for example, different interferenceconditions. By the split power control, a more optimal multi-slot systemcan be obtained with regard to power used and the quality of thereceived signal. An optimized use of transmitting power means a loweraverage transmitting power, which leads to a longer battery life. Theaverage interference level in the system is also decreased resulting ina higher system capacity.

In a second embodiment of the invention, all the time slots have theirown control channels through which measurement reports are transmitted,but power control is performed for each channel through only one singlecontrol channel in the direction from the fixed network to a mobilestation.

Similar kinds of improvements in the performance of the system, albeitof less importance, are obtained by using a common, parallel controlchannel for all time slots assigned to a mobile station so that acombination of measurement results of all the time slots, for example,average value, is transmitted to the fixed radio network over the commoncontrol channel. The fixed radio network controls the transmitting powerof the mobile station through the same common control channel.

The reliability of handover decisions can also be improved in amulti-slot system in cases wherein every time slot assigned to a mobilestation is independently measured in accordance with the invention, andthe handover decision is made on the basis of a combination of themeasurement results, such as average value, or on the basis of thepoorest time slot.

The implementation may be especially simple if adjacent time slots areemployed. Consequently, it will be easier to carry out variousmeasurements the remaining part of the frame, and increasing the numberof frequency synthesizers in the receiver of the mobile station isavoided. In the GSM system, it is especially advantageous to implementthe invention by two time slots.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be described in greater detail bythe primary embodiments with reference to the accompanying drawings, inwhich:

FIG. 1 illustrates a section of a mobile system in which the inventioncan be applied, and

FIGS. 2, 3, 4 and 5 illustrate a TDMA frame format,

FIG. 6 illustrates a TCH/F+SACCH multiframe,

FIG. 7 illustrates a conventional data transmission in one time slot,

FIG. 8 illustrates data transmission in accordance with the invention intwo time slots,

FIG. 9 illustrates the timing of transmission, reception andmeasurements in a data transmission of one time slot,

FIG. 10 illustrates the timing of transmission, reception andmeasurements in a data transmission of two time slots.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

The present invention can be applied to high-speed data transmission inmost of the digital mobile systems of the TDMA type such as, forexample, the Pan-European digital mobile system GSM, DSC1800 (DigitalCommunication System), UMTS (Universal Mobile Telecommunication System),FPLMTS (Future Public Land Mobile Telecommunication System), etc.

A mobile system of the GSM type is illustrated as an example. GSM(Global System for Mobile Communications) is a Pan-European mobilesystem. FIG. 1 very briefly illustrates the basic elements of the GSMsystem without going any further into the details or other sub-sectionsof the system. For a closer description of the GSM system, the GSMrecommendations and "The GSM System for Mobile Communications", by M.Mouly & M. Pautet, Palaiseau, France, 1992, ISBN: 2-9507190-0-7 isreferred to.

A mobile services switching centre MSC handles the connecting ofincoming and outgoing calls. It performs functions similar to those ofan exchange of a public telephone network (PSTN). In addition to these,it also performs functions characteristic of mobile communications only,such as subscriber location management in co-operation with thesubscriber registers of the network. As subscriber registers, the GSMsystem at least includes the home location register HLR and the visitorlocation register VLR which are not shown in FIG. 1. More accurateinformation of the location of the subscriber, usually the accuracy ofthe location area, is stored in the visitor location register, therebeing typically one VLR per each mobile services switching centre MSC,while the HLR knows which VLR area the mobile station MS is visiting.The mobile stations MS are connected to the centre MSC by base stationsystems. The base station system consists of a base station controllerBSC and base stations BTS. One base station controller is used tocontrol several base stations BTS. The tasks of the BSC include, amongother things, handovers in cases in which the handover is performedwithin the base station, or between two base stations controlled by thesame BSC. FIG. 1 only shows, for reasons of clarity, a base stationsystem in which nine base stations BTS1-BTS9 are connected to a basestation controller BSC, the radio coverage area of which base stationsforms the corresponding radio cells C1-C9.

The GSM system is a time division multiple access (TDMA) system in whichthe time division traffic on the radio path takes place in successiveTDMA frames each of which consists of several time slots. In each timeslot, a short information packet is sent as a radio frequency burst of afinite duration, which burst consists of a number of modulated bits. Forthe most part, time slots are used for the transmission of controlchannels and traffic channels. On the traffic channels, speech and dataare transmitted. On the control channels, signalling between a basestation and mobile subscriber stations is carried out.

Channel structures used in radio interfaces of the GSM system aredescribed in closer detail in the ETSI/GSM recommendation 05.02. TheTDMA frame format of the GSM system is illustrated as an example inFIGS. 2-5. FIG. 5 illustrates a TDMA basic frame which includes eighttime slots 0-7 used as traffic channels or control channels. Thus, onlyone radio frequency burst shorter than the duration of the time slot istransmitted in each time slot. As soon as one TDMA basic frame ends intime slot 7, the time slot 0 of the next basic frame immediately begins.Thus, 26 or 51 successive TDMA frames form a multiframe depending onwhether a traffic channel or a control channel structure is in question,as illustrated in FIG. 4. A superframe consists of 51 or 26 successivemultiframes depending on whether the multiframes have 26 or 51 frames,as illustrated in FIG. 3. A hyperframe is formed of 2048 superframes, asillustrated in FIG. 2. The hyperframe is the largest successive frameunit, whose ending starts a new, similar hyperframe.

FIG. 6 illustrates a structure of a full-speed traffic channelTCH/F-SACCH/TF defined by the aforemention recommendation, in whichstructure a multiframe includes 24 full-speed traffic channel framesTCH, one parallel control channel frame SACCH and a dummy frame IDLE. Ineach time slot assigned to be used as traffic channels, the controlchannel SACCH and a dummy time slot are repeated every 26 time slots.The positions of the frames SACCH and IDLE are different for time slots0, 2, 4 and 6 than for time slots 1, 3, 5, and 7. What is illustrated inFIG. 7 is valid for time slots 0, 2, 4 and 6. In time slots 1, 3, 5 and7, frames IDLE and SACCH exchange places. The control channel SACCH isused for reporting the measurement results from the mobile station tothe fixed radio network, and for controlling the mobile station, forexample, providing power adjustment, from the fixed radio network.

In normal operation, at the beginning of a call a mobile station MS isassigned one time slot from a carrier wave as a traffic channel (singleslot access). The mobile station MS synchronizes into this time slot totransmit and receive radio frequency bursts. In FIG. 7, for example, amobile station MS is locked to the time slot 0 of a frame. Channelcoding, interleaving, burst formation, and modulation 70 are carried outto the data to be transmitted DATAIN, after which operations the radiofrequency burst is transmitted in the time slot 0 of each TDMA frame. Inthe remaining part of the frame, the MS carries out various kinds ofmeasurements, as will be described below.

In accordance with the invention, a mobile station MS requiring datatransmission of higher speed than one traffic channel can offer, isassigned two or more time slots from the same frame.

The multi-slot technique according to the invention requires certainadditional features in the signalling in connection with traffic channelallocation. During the call set-up time, assigning a traffic channel toa mobile station is carried out by an assignment command which istransmitted to the mobile station by the fixed network. This messagemust contain the data of all the traffic channels that are assigned to amobile station MS for high-speed data transmission according to theinvention. Already by now, the GSM system must be able to address twohalf-speed traffic channels in the same assignment command, which is whythe message contains descriptions and modes for both the first as wellas the second traffic channel. The present assignment command can easilybe expanded to cover the addressing of at least two time slots, i.e.full-speed traffic channels. An assignment command is described in theGSM recommendation 04.08, version 4.5.0, June 1993, pp. 168-170. Channeladdressing in accordance with the invention can be performed in theassignment command data elements Mode of first channel, Mode of secondchannel, and Channel Description Information element, which aredescribed in greater detail in the GSM recommendation 04.08, version4.5.0, June 1993, pp. 316-350. For addressing more than two time slots,a new message must be determined. Due to the fact that all the channelsaddressed are of the same type of channel, TCH/F, the message can belimited to describe the type of the first channel and then the totalnumber of channels required. In such a case, the message would be rathershort and simple.

Correspondingly, in case of a handover, the handover command must beable to address two or more time slots in the same frame. In the GSMsystem, the handover command contains the same data fields as describedabove in connection with the assignment command, and thus it can beapplied to the requirements of the invention with similar changes. Thehandover command is described in the GSM recommendation 04.08, version4.5.0, June 1993, pp. 184-189.

A second alternative is to employ a dedicated assignment command foreach time slot.

In both cases, both outgoing and incoming call set-up messages (SETUP)of a mobile station must contain information about the actual channelrequirements, in other words, the number of time slots needed. Thisinformation may be included in the Bearer Capability Information elementBCIE. The BCIE is described in the GSM recommendation 04.08, version4.5.0, pp. 423-431.

FIG. 8 shows an example in which a mobile station MS is assignedsuccessive time slots 0 and 1 from the same TDMA frame. A high-speeddata signal DATAIN to be transferred over the radio path is split in thedivider 82 into a necessary number of data signals of lower speed DATA1and DATA2. Channel coding, interleaving, burst formation and modulation80, and, correspondingly, 81, are separately carried out to each datasignal of lower speed DATA1 and DATA2, after which each data signal istransmitted as a radio frequency burst in its dedicated time slot 0 and1, respectively. As soon as the lower speed data signals DATA1 and DATA2are separately transmitted over the radio path, demodulation,deinterleaving and channel decoding 83 and, correspondingly, 84, of thesignals are separately performed at the receiving end, after which thesignals DATA1 and DATA2 are combined into the original high-speed signalDATAOUT in the combiner 85 at the receiving end.

On the fixed network side, the functions of blocks 80, 81, 83, 84 ofFIG. 8, in other words, channel coding, interleaving, burst formationand modulation, and, correspondingly, demodulation, deinterleaving andchannel decoding are located advantageously at the base station BTS. Thebase station BTS has a separate, parallel handling for each time slot.The divider 82 and the combiner 85 can, in turn, be assigned, as needed,to any network element such as a base station BTS, a base stationcontroller BSC, or a mobile services switching centre MSC. In cases thedivider 82 and the combiner 85 are located in another network elementthan the base station BTS, the data signals of lower speed DATA1 andDATA2 are transmitted between that element and the base station BTSsimilarly to signals on normal traffic channels.

In a fixed network of the GSM system, various functions relating tospeech coding and rate adaptation are concentrated in a TRCU(Transcoder/Rate Adaptor Unit). The TRCU may be located in severalalternative places in the system according to choices made by themanufacturer. Typically, the TRCU is placed at the mobile servicesswitching centre MSC, but it may also be a part of a base stationcontroller BSC or a base station BTS. In cases the TRCU is placed apartfrom a base station BTS, information is transmitted between the basestation and the transcoder/rate adaptor unit TRCU in so-called TRAUframes. The function of the transcoder/rate adaptor unit is defined inthe GSM recommendation 08.60. A combiner 85 and a divider 83 inaccordance with the invention may be placed with this transcoder/rateadaptor unit TRCU.

In a mobile station MS, the blocks 80, 81, 83 and 84 of FIG. 8, in otherwords, channel coding, interleaving, burst formation and modulation,and, correspondingly, demodulation, deinterleaving and channel decoding,are advantageously implemented by a processing unit common to all timeslots, at least in an embodiment of two time slots.

As is well known, mobile stations MS can freely roam in the area of amobile system from one cell to another. If a mobile station is nothandling a call, switching from one cell to another includes simply aregistration to a new cell. If a mobile station MS is handling a callduring the switching of cells, the call must also be switched from onebase station to another by a way which causes as little disturbance tothe call as possible. Switching cells during a call is called ahandover. A handover can also be carried out within a cell from onetraffic channel to another.

If a mobile station MS roams in a radio network, a handover from theserving cell to a neighbouring cell is normally performed either (1) asthe measurement results of the mobile station MS and/or the base stationBTS indicate a low signal level and/or quality from the current servingcell and a better signal level can be obtained from a neighbouring cell,or (2) as a neighbouring cell enables communication at lowertransmitting power levels, in other words, as the mobile station MS isin a border area between cells. In radio networks, the aim is to avoidunnecessarily high power levels and thus interference elsewhere in thenetwork.

In FIG. 9, a mobile station is in a normal manner locked into a timeslot 0 of a frame. In the time slot 0, the traffic channel TCH assignedto the mobile station is transmitted. In addition, in every 26th frameof the same time slot a parallel control channel SACCH is transmitted,as described in connection with FIG. 6. According to the GSMrecommendations, a mobile station MS monitors (measures) the level andquality of the downlink signal of the serving cell in time slot 0 on thetraffic channel TCH assigned to it. During the other time slots, themobile station MS measures the levels of the downlink signals of theneighbouring cells of the serving cell. All the measurement results ofthe mobile station MS are regularly transmitted to a base stationcontroller BSC through a parallel control channel SACCH associated withthe time slot of traffic channel TCH. The base station BTS monitors(measures) the level and quality of the uplink signal received from eachof the mobile stations MS served by the respective base station BTS.

On the basis of the measurement results, the BSC controls the power ofthe mobile station MS by power control commands transmitted to the MS inthe downlink direction through the control channel SACCH, and makes thehandover decisions.

Procedures and calculations used in radio networks for determiningsuitable transmitting power levels are referred to as power controlalgorithms. There are many different types of algorithms, but usuallytheir aim is the lowest possible transmitting power level and, thus, lowinterference levels.

Decisions on handovers during on-going calls are made by a base stationcontroller BSC on the basis of various handover parameters assigned toeach cell, and on the basis of measurement results reported by a mobilestation MS and base stations BTS. A handover is normally carried out onthe basis of criteria of the radio path, but it can be performed due toother reasons as well, for example, load sharing. The procedures andcalculations used as the basis of a handover decision are referred to asa handover algorithm. Alternatively, all handover decisions can be madeat a mobile services switching centre MSC to which all the measurementresults are in such a case transmitted. A MSC also controls at leastthose handovers occurring from the area of one base station controllerto the area of another.

As a mobile station is, in accordance with the invention, assigned aplurality of time slots within the same frame for high-speed datatransmission, the mobile station measures the level and quality of thedownlink signal separately in each time slot assigned to it. In theexample of FIG. 10, a mobile station is assigned the adjacent time slots0 and 1. The mobile station MS measures the level and quality of thedownlink signal of the serving cell independently in time slot 0 and 1on the traffic channel TCH assigned to it. During the other time slots,the mobile station MS measures the levels of the downlink signals of theneighbouring cells of the serving cell.

In the primary embodiment of the present invention, each time slotassigned to a mobile station MS, the traffic channel TCH, has adedicated parallel control channel SACCH through which the measurementresults relating to the respective time slot are transmitted to a basestation controller BSC.

A base station controller BSC controls the transmitting power of amobile station MS separately in each time slot, in other words, on thetraffic channel TCH, by power control commands transmitted to the mobilestation MS in the downlink direction through the control channel SACCHof the traffic channel. Power control on an individual channel isotherwise carried out in accordance with the GSM recommendations.

Alternatively, a base station controller BSC may control thetransmitting power levels of all the time slots by a common powercontrol command transmitted to the mobile station MS in the downlinkdirection through one of the parallel control channels.

The handover decision is made by the base station controller on thebasis of a combination of measurement results of two or more time slotsassigned to a mobile station, or on the basis of a measurement result ofthe poorest time slot. As the decision to carry out a handover is made,a modified handover command is transmitted to the mobile station MS, asdescribed above.

In a second embodiment of the present invention, all the time slotsassigned to a mobile station MS, the traffic channels TCH, have acommon, parallel control channel SACCH through which a combination ofmeasurement results of the time slots is transmitted to a base stationcontroller BSC. This combination of the measurement results can, forexample, be the average value of the measurement results of the varioustime slots.

The base station controller BSC controls the transmitting power levelsof the mobile station MS jointly in all the time slots, in other words,on the traffic channels TCH, by common power control commandstransmitted to the mobile station MS in the downlink direction throughthe common control channel SACCH.

The handover decision is made by the base station controller on thebasis of a combination of measurement results of either all or some ofthe time slots assigned to a mobile station MS. As the decision to carryout a handover is made, a modified handover command is transmitted tothe mobile station as described above.

The drawing figures and the description referring to them are onlyintended to illustrate the present invention. The method and arrangementof the invention may vary in details within the scope of the attachedclaims.

We claim:
 1. A method for power control of a mobile station in a mobiletelecommunications system, the method comprising:transmitting data overa radio path between a mobile station and a base station of a fixedradio network as bursts in time slots of successive frames; allocatingthe mobile station at least two time slots in each frame fortransmitting a high-speed data signal having a data rate which is higherthan that supported by use of one time slot in each frame; splitting thehigh-speed data signal into a plurality of lower-speed sub-signalscorresponding in number to the number of allocated time slots; thetransmitting including transmitting the lower-speed sub-signals over theradio path as respective separate bursts in each of the allocated timeslots; upon reception of the separate bursts transmitted over the radiopath, combining the lower-speed sub-signals, thereby restoring thehigh-speed data signal; measuring, at the mobile station in each timeslot allocated to the mobile station, at least one characteristic of areceived signal, the characteristic selected from the group consistingof signal level and signal quality; and controlling the transmittingpower of the mobile station on the basis of one of (a) a combination ofmeasurement results of two or more time slots assigned to the mobilestation, and (b) a measurement result of the poorest time slot inrelation to the at least one characteristic.
 2. A method as claimed inclaim 1, further comprising:assigning the mobile station a parallelcontrol channel common to all the time slots assigned to the mobilestation; transmitting a combination of the measurement results of allthe time slots assigned to the mobile station from the mobile station tothe fixed radio network through the common, parallel control channel;and controlling the transmitting power of the mobile station in all thetime slots assigned to the mobile station through the common, parallelcontrol channel.
 3. A method as claimed in claim 1, furthercomprising:assigning the mobile station a dedicated parallel controlchannel for each time slot assigned to the mobile station; transmittingthe measurement result of each time slot assigned to the mobile station,separately, from the mobile station to the fixed radio network throughthe parallel control channel corresponding to each respective the timeslot; and controlling the transmitting power of the mobile station ineach time slot assigned to the mobile station through the controlchannel corresponding to the respective time slot.
 4. A method asclaimed in claim 1, further comprising:assigning the mobile station adedicated parallel control channel for each time slot assigned to themobile station; transmitting the measurement result of each time slotassigned to the mobile stations, separately, from the mobile station tothe fixed radio network through the parallel control channelcorresponding to each respective the time slot; and controlling thetransmitting power of the mobile station in all the time slots assignedto the mobile station through one the common, parallel control channel.5. A handover method in a mobile telecommunications system, the methodcomprising:transmitting data over a radio path between a mobile stationand a base station of a fixed radio network as bursts in time slots ofsuccessive frames; allocating to the mobile station at least two timeslots in each frame for transmitting a high-speed data signal having adata rate which is higher than that supported by use of one time slot ineach frame; splitting the high-speed data signal into a plurality oflower-speed sub-signals corresponding in number to the number ofallocated time slots; the transmitting including transmitting thelower-speed sub-signals over the radio path as respective separatebursts in each of the allocated time slots; upon reception of theseparate bursts transmitted over the radio path, combining thelower-speed sub-signals, thereby restoring the high-speed data signal;measuring, at the mobile station in each time slot allocated to themobile station, at least one characteristic of a received signal, theone characteristic selected from the group consisting of signal leveland signal quality; and making a handover decision in regard to themobile station on the basis of one of (a) a combination of measurementresults of two or more time slots assigned to the mobile station, and(b) a measurement result of the poorest time slot in relation to the atleast one characteristic.
 6. A method as claimed in claim 5, furthercomprising:assigning the mobile station a parallel control channelcommon to all the time slots assigned to the mobile station; andtransmitting a combination of the measurement results of all the timeslots assigned to the mobile station from the mobile station to thefixed radio network through the common, parallel control channel.
 7. Amethod as claimed in claim 5, further comprising:assigning the mobilestation a dedicated parallel control channel for each time slot assignedto the mobile station; and transmitting the measurement result of eachtime slot assigned to the mobile station, separately, from the mobilestation to the fixed radio network through the parallel control channelcorresponding to each respective the time slot.
 8. A control arrangementof a mobile station in a mobile telecommunications system in which datais transmitted over a radio path between the mobile station and a basestation of a fixed radio network as bursts in time slots of successiveframes, the arrangement comprising:means for allocating the mobilestation at least two time slots in each frame for transmitting ahigh-speed data signal having a data rate which is higher than thatsupported by use of one time slot in each frame; means for splitting thehigh-speed data signal into a plurality of lower-speed sub-signalscorresponding in number to the number of allocated time slots; means fortransmitting the lower-speed sub-signals over the radio path asrespective separate bursts in each of allocated time slots; means forcombining the lower-speed sub-signals, upon reception of the separatebursts transmitted over the radio path, and thereby restoring thehigh-speed data signal; the mobile station being arranged to measure atleast one characteristic of a received signal, the characteristicselected from the group consisting of signal level and signal quality,in each time slot allocated to the mobile station; and the fixed radionetwork being arranged to at least one of (a) control the transmittingpower of the mobile station and (b) make a handover decision on thebasis of (b1) a combination of measurement results of two or more timeslots assigned to the mobile station, and (b2) a measurement result ofthe poorest time slot in relation to the at least one characteristic. 9.An arrangement as claimed in claim 8, wherein:the mobile station has aparallel control channel common to all the time slots assigned to themobile station; and the mobile station is arranged to transmit acombination of measurement results of all the time slots assigned to themobile station from the mobile station to the fixed radio networkthrough the common, parallel control channel.
 10. An arrangement asclaimed in claim 9, wherein:the fixed radio network is arranged tocontrol the transmitting power of the mobile station in all the timeslots assigned to the mobile station, through the common, parallelcontrol channel.
 11. An arrangement as claimed in claim 8, wherein:themobile station has a dedicated, parallel control channel for each of thetime slots assigned to the mobile station; and the mobile station isarranged to separately transmit a combination of the measurement resultsof all the time slots assigned to the mobile station to a fixed radionetwork through the parallel control channel corresponding to eachrespective the time slot.
 12. An arrangement as claim in claim 11,wherein:the fixed network is arranged to control the transmitting powerof the mobile station in each time slot assigned to the mobile station,through the parallel control channel corresponding to each respectivethe time slot.
 13. An arrangement as claimed in claim 11, wherein:thefixed network is arranged to control the transmitting power of themobile station in all the time slots assigned to the mobile station,through one parallel control channel.